more info on your computer hard drive ram cpu etc could help.
download a trial of A Squared from here:-
do not in stall it yet
then start your computer keep tapping the F8 key , then select SAFE MODE then install and run the A Sguared
follow that by your anti virus, this is the best way to clean out spyware and some other nasties.
too much spyware can slow down a computer to a snails pace